Stability over 36 months of a new liquid 10% polyclonal immunoglobulin product (IgPro10, Privigen) stabilized with L-proline.

BACKGROUND AND OBJECTIVES: IgPro10 (Privigen) is a new liquid intravenous immunoglobulin (IVIG) product that is formulated with 250 mM L-proline at pH 4.8. A 3-year study was performed to assess its stability.

MATERIALS AND METHODS: Physicochemical, biological and immunological parameters of Privigen were assessed during storage under controlled conditions over up to 36 months at 25 degrees C.

RESULTS: Privigen was shown to be stable after storage for 3 years at room temperature (25 degrees C). Of all parameters tested, only a few showed changes during storage. The appearance of the solution complied with the specifications given by the European Pharmacopeia over the full study period, with a single exception. The IgG fraction in Privigen displayed high purity (> or = 98%), which did not change during storage over 36 months. No relevant amounts of aggregated IgG molecules were formed in Privigen samples and the ratio between monomers and dimers shifted slightly towards the equilibrium over time. Testing of reference antibody contents and the Fc function demonstrated that the biological activity and effector functions of Privigen were preserved over the full study period of 36 months.

CONCLUSION: Thirty-six months room temperature stability of Privigen was achieved at pH 4.8 with an innovative formulation containing the physiological stabilizer L-proline.